This invention is directed to an environmental strip curtain system, and in particular, to an environmental strip curtain system in which an improved support bar construction permits strips to be easily installed, removed, replaced or adjusted.
Environmental strip curtain systems are known in the art. Flexible, transparent plastic strips are used for providing a thermal barrier between the opposite sides of an opening such as a doorway or the like. The plastic strips are suspended adjacent the top of the opening to the bottom of the opening and function as a thermal barrier between the opposite sides of the opening. The environmental strip curtain eliminates the need for a solid door which must be opened for ingress and egress. The plastic strips are conventionally constructed and defined to be suspended in a vertical, partially overlapping relationship which permits an individual to readily part the strips by hand to move through the strips and the opening. After the individual has walked through the opening, the weight of the plastic strips automatically causes the hanging strips to assume their closed, overlapping vertical relationship. The plastic strips are also manufactured with sufficient structural rigidity to permit carts, dollies, fork lift trucks and similar conveyances to be moved or driven through the plastic strips without permanent damage to the strips or degradation of the thermal barrier.
Environmental strip curtains have been found to be very advantageous to control dust and smoke, maintain stable temperatures, reduce product spoilage, lessen sound levels, restrict drafts, insects, sparks, and flying chips, cut cooling and heating maintenance and to generally save up to 50% in energy requirements. These environmental strip curtains have been found to increase productivity in food processing and other temperature controlled plants, laboratories, warehouses, refrigerated trucks, hospitals, clean rooms, computer installations and other interior and exterior applications where environmental isolation is necessary or desirable.
The particular designs for the environmental strip curtain systems vary. An early design involves clamping the strips in an overlapping relationship between two rods and then securing the apparatus to the opening by fasteners. Another design requires that a permanent heat-bonded loop be formed on the top end of the strips, with a rod inserted through the loops and attached to the opening. The disadvantage of these designs is that they require considerable effort to install the environmental strip curtains as well as difficulties in replacing damaged strips.
Another design is described in U.S. Pat. No. 4,384,606. Loops are formed on the top end of the strip not by permanently heat bonding the plastic but by securing the plastic with fasteners such as nuts and bolts. A rod is then inserted through the loops and attached to the opening. This design has the advantage that if one strip becomes damaged, it may be removed from the rod by releasing the nuts and bolts securing the loop. Thus, it is not necessary to first slide off all the other strips between the defective strip and the end of the rod to replace the defective strip.
The environmental curtain strip described in U.S. Pat. No. 4,384,606 has several disadvantages. First, the installation, removal and replacement of strips still necessitates considerable effort in that the loop must be formed or straightened and the multiple nuts and bolts must be secured or released. Second, the rod must be loosened from the opening to allow the loop in the strip to be withdrawn from the rod. Third, the width of overlap between strips cannot be changed without changing the width of the loop.
Accordingly, an environmental strip curtain system is desired which allows for easy installation, removal, replacement and adjustment of the plastic strips.